Patent US3781283A successfully refreshed from Google Patents.
US3781283A
Expired / Lapsed
US
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Process for preparing cephem-4-carboxylic acid esters
Assignee: Hoechst AG
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Filing: 1971-12-28
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Granted: 1973-12-25
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Expires: 1991-12-28
Abstract
Abstract PROCESS FOR PREPARING A CEPHEM-CARBOXYLIC ACID ESTER OF THE FORMULA 7-(R-NH-),2-(R''-OOC-),3-CH3-2-CEPHEM BY HEATING A PENICILLIN OXIDE OF THE FORMULA 6-(R-NH-),2-(R''-OOC-),3,3-DI(CH3-)PENAM IN A SOLVENT WITH A PHOSPHONIUM SALT OF THE FORMULA R1-P(+)(-R2)(-R3)-R4 X(-) IN THE FORMULAS; R IS ACYL; R'' IS ALKYL, SUBSTITUTED ALKYL, CYCLOALKYL, OR ARYL; R1, R2 ARE EACH SUBSTITUTED OR UNSUBSTITUTED HYDROCARBON; R4 IS METHYL SUBSTITUTED BY AN ELECTRON-ATTRACTING GROUP, AND MAY CONTAIN A FURTHER SUBSTITUENT; AND ? IS AN ANION.
Inventors
- 👤 D Bormann
- 👤 M Worm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:20
CPC Classifications
C; C07; C07D; C07D205/00; C07D205/02; C07D205/06; C07D205/08; C07F; C07F9/00; C07F9/02; C07F9/28; C07F9/54; C07F9/5407; C07F9/547; C07F9/553; C07F9/568
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-24 | 1977-06-25 | 1977-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-24 | 1981-06-25 | 1981-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-24 | 1985-06-25 | 1985-12-25 | $7700.00 | Window Closed / Lapsed |